In certain situations when users of digital imaging apparatuses perform an imaging procedure, for example, with high resolution/zoom factor, low sensitivity sensor, long exposure time (night-shot) and with a lightweight device (e.g. mobile phone), hand shaking can very easily result blurred, out-of-focus images. This effect can be avoided with image stabilizer application (or anti-shake).
Basically there are three ways to solve the problem described above: 1) using a rigid fixture for the camera (e.g. tripod) during shooting, 2) increase the weight of the camera device so that shaking has less effect or 3) use an built-in stabilization system. Since using tripod is not always possible and increasing weight is less practical, the stabilization is a better feature for small mobile products including camera unit.
Image stabilization has not yet widely being implemented in commercially available mobile phones, but it exists already in mid-range digital still cameras (e.g. Panasonic models [1]). In cameras the balancing effect can be implemented by moving the optics (lens) or sensor. From these two, the moving of the lens results much more practical implementation sizewise.
European Patent Application EP-0 253 375 presents a solution in which image sensor is moved. However, this solution is not suitable for commercial digital cameras or mobile phones. This solution is aimed to the mask matching of the integrated circuits. These applications require an option to correct the inclination of the solid-state image sensor.
European Patent Application EP-0 572 976 presents a solution in which part of the optics is moved. This is performed based on the response that is caused by the external source detected in connection with the imaging process. However, this publication doesn't speak out the technical implementation of the optical image stabilizer unit that performs the actuation of the optics.
Additionally, the prior art solutions must have the separate arrangements to detect the position of the corrective lens relative to the sensor. In order to measure this there must be arranged some particular detector to measure this. This complicates the implementations of the optical image stabilizer units.